1. Field of the Invention
The present invention relates to medical devices, and particularly to an expandable sheath for insertion of an arterial catheter.
2. Description of the Related Art
Less invasive medical procedures for various operations are, of course, highly desirable, as they result in less trauma for the patient, faster healing, less time spent in the hospital, less expense to the patient, and the ability for the patient to return to his or her work or normal lifestyle more rapidly. This is particularly true in cardiac procedures. If a surgical procedure can be accomplished without an open chest, or open-heart, surgery, such less invasive practices are much more desirable.
An example of such is the opening of various coronary arteries that have become obstructed by cholesterol deposits. The correction of this condition originally required surgery to access the interiors of the arteries directly for curettage. More recently, such arterial deposits have been flattened or pressed against, or into, the walls of the arteries by the balloon angioplasty procedure, wherein an inflatable device is inserted into the artery and expanded to widen the artery for proper blood flow. Accessing the femoral artery in one of the thighs of the patient, and working a catheter through the artery until reaching the desired target area in the coronary artery conventionally accomplish this procedure. The balloon is expanded to widen the artery when the balloon reaches the target area. While this procedure is clearly less invasive than open chest surgery, the length of the catheter and sheath required, as well as the delicate manipulation of the catheter and sheath through such a relatively long pathway, make this a relatively intricate procedure. Various other procedures, such as coronary angioplasty, coronary arteriography, cardiac catheterization, etc., also typically involve the insertion of catheters, guides, and the like through an introducer sheath in the femoral artery.
More recently, there has been interest in developing techniques for access of coronary arteries through the radial artery in the wrist or lower arm of the patient. This procedure has advantages, including the far shorter distance required for manipulation of the distal end of the catheter from the entry site to the coronary artery. This also generally results in fewer traumas to the patient, as the percutaneous opening need not be so large when accessing the smaller radial artery in comparison to the femoral artery. However, the radial artery is a smaller diameter vessel than the femoral artery. Generally, it is desirable to keep the puncture of the vessel as small as possible. Nevertheless, coronary procedures often require the use of larger diameter guides, catheters, etc., than desirable in the radial artery.
The medical profession uses a measurement system known as the French system for the diameters of these various sheaths and catheters. In the French system, one French is equal to one third of a millimeter, i.e., 3 F=1.0 mm, with a linear correspondence between the French and metric dimensions. Typical guide and sheath diameters for use in a radial artery intervention procedure might be 2.00 mm or 6 French for the sheath, but the use of a larger 2.33 mm or 7 French guide is desirable in order to provide sufficient volume within the guide for the catheters and guides used for coronary procedures.
Thus, an expandable sheath and system for intravascular insertion of a medical implement using the same solving the aforementioned problems is desired.